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src/func-name-inferrer.h

+// Copyright 2006-2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_FUNC_NAME_INFERRER_H_
+#define V8_FUNC_NAME_INFERRER_H_
+
+namespace v8 {
+namespace internal {
+
+// FuncNameInferrer is a stateful class that is used to perform name
+// inference for anonymous functions during static analysis of source code.
+// Inference is performed in cases when an anonymous function is assigned
+// to a variable or a property (see test-func-name-inference.cc for examples.)
+//
+// The basic idea is that during AST traversal LHSs of expressions are
+// always visited before RHSs. Thus, during visiting the LHS, a name can be
+// collected, and during visiting the RHS, a function literal can be collected.
+// Inference is performed while leaving the assignment node.
+class FuncNameInferrer BASE_EMBEDDED {
+ public:
+  FuncNameInferrer()
+      : entries_stack_(10),
+        names_stack_(5),
+        func_to_infer_(NULL),
+        dot_(Factory::NewStringFromAscii(CStrVector("."))) {
+  }
+
+  // Returns whether we have entered name collection state.
+  bool IsOpen() const { return !entries_stack_.is_empty(); }
+
+  // Pushes an enclosing the name of enclosing function onto names stack.
+  void PushEnclosingName(Handle<String> name);
+
+  // Enters name collection state.
+  void Enter() {
+    entries_stack_.Add(names_stack_.length());
+  }
+
+  // Leaves names collection state.
+  void Leave() {
+    ASSERT(IsOpen());
+    names_stack_.Rewind(entries_stack_.RemoveLast());
+  }
+
+  // Pushes an encountered name onto names stack when in collection state.
+  void PushName(Handle<String> name) {
+    if (IsOpen()) {
+      names_stack_.Add(name);
+    }
+  }
+
+  // Sets a function to infer name for.
+  void SetFuncToInfer(FunctionLiteral* func_to_infer) {
+    if (IsOpen()) {
+      ASSERT(func_to_infer_ == NULL);
+      func_to_infer_ = func_to_infer;
+    }
+  }
+
+  // Infers a function name and leaves names collection state.
+  void InferAndLeave() {
+    ASSERT(IsOpen());
+    MaybeInferFunctionName();
+    Leave();
+  }
+
+ private:
+  // Constructs a full name in dotted notation from gathered names.
+  Handle<String> MakeNameFromStack();
+
+  // A helper function for MakeNameFromStack.
+  Handle<String> MakeNameFromStackHelper(int pos, Handle<String> prev);
+
+  // Performs name inferring if there is a function to infer name for.
+  void MaybeInferFunctionName();
+
+  List<int> entries_stack_;
+  List<Handle<String> > names_stack_;
+  FunctionLiteral* func_to_infer_;
+  Handle<String> dot_;
+
+  DISALLOW_COPY_AND_ASSIGN(FuncNameInferrer);
+};
+
+
+// A wrapper class that automatically calls InferAndLeave when
+// leaving scope.
+class ScopedFuncNameInferrer BASE_EMBEDDED {
+ public:
+  explicit ScopedFuncNameInferrer(FuncNameInferrer* inferrer)
+      : inferrer_(inferrer),
+        is_entered_(false) {}
+
+  ~ScopedFuncNameInferrer() {
+    if (is_entered_) {
+      inferrer_->InferAndLeave();
+    }
+  }
+
+  // Triggers the wrapped inferrer into name collection state.
+  void Enter() {
+    inferrer_->Enter();
+    is_entered_ = true;
+  }
+
+ private:
+  FuncNameInferrer* inferrer_;
+  bool is_entered_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedFuncNameInferrer);
+};
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_FUNC_NAME_INFERRER_H_